Composite for raising recovery efficiency of crude

The present invention relates to a surfactant-containing compound for raising producible oil index in tertiary oil recovery. Said surfactant is made of long-chain olefine obtained by propylene oligomerization and making it undergo the processes of alkylation, sulfonation and neutralization. Under the condition of low alkali it can form ultra-low interfacial tension of 10 to the minus third mN/m between oil and water, and possesses strong adaptability for various alkalies.